<template>
    <Teleport :to="appendTo">
        <transition name="p-overlaypanel" @enter="onEnter" @leave="onLeave" @after-leave="onAfterLeave">
            <div :class="containerClass" v-if="visible" :ref="containerRef" v-bind="$attrs" @click="onOverlayClick">
                <div class="p-overlaypanel-content" @click="onContentClick" @mousedown="onContentClick">
                    <slot></slot>
                </div>
                <button class="p-overlaypanel-close p-link" @click="hide" v-if="showCloseIcon" :aria-label="ariaCloseLabel" type="button" v-ripple>
                    <span class="p-overlaypanel-close-icon pi pi-times"></span>
                </button>
            </div>
        </transition>
    </Teleport>
</template>

<script>
import {UniqueComponentId,DomHandler,ConnectedOverlayScrollHandler,ZIndexUtils} from 'primevue/utils';
import OverlayEventBus from 'primevue/overlayeventbus';
import Ripple from 'primevue/ripple';

export default {
    name: 'OverlayPanel',
    inheritAttrs: false,
    props: {
		dismissable: {
			type: Boolean,
			default: true
		},
		showCloseIcon: {
			type: Boolean,
			default: false
		},
        appendTo: {
			type: String,
			default: 'body'
		},
        baseZIndex: {
            type: Number,
            default: 0
        },
        autoZIndex: {
            type: Boolean,
            default: true
        },
        ariaCloseLabel: {
            type: String,
            default: 'close'
        },
        breakpoints: {
            type: Object,
            default: null
        }
    },
    emits: ['show', 'hide'],
    data() {
        return {
            visible: false
        }
    },
    selfClick: false,
    target: null,
    eventTarget: null,
    outsideClickListener: null,
    scrollHandler: null,
    resizeListener: null,
    container: null,
    styleElement: null,
    overlayEventListener: null,
    beforeUnmount() {
        if (this.dismissable) {
            this.unbindOutsideClickListener();
        }

        if (this.scrollHandler) {
            this.scrollHandler.destroy();
            this.scrollHandler = null;
        }
        this.destroyStyle();
        this.unbindResizeListener();
        this.target = null;

        if (this.container && this.autoZIndex) {
            ZIndexUtils.clear(this.container);
        }

        if (this.overlayEventListener) {
            OverlayEventBus.off('overlay-click', this.overlayEventListener);
            this.overlayEventListener = null;
        }

        this.container = null;
    },
    mounted() {
        if (this.breakpoints) {
            this.createStyle();
        }
    },
    methods: {
        toggle(event, target) {
            if (this.visible)
                this.hide();
            else
                this.show(event, target);
        },
        show(event, target) {
            this.visible = true;
            this.eventTarget = event.currentTarget;
            this.target = target || event.currentTarget;
        },
        hide() {
            this.visible = false;
        },
        onContentClick() {
            this.selfClick = true;
        },
        onEnter(el) {
            this.container.setAttribute(this.attributeSelector, '');
            this.alignOverlay();
            if (this.dismissable) {
                this.bindOutsideClickListener();
            }

            this.bindScrollListener();
            this.bindResizeListener();

            if (this.autoZIndex) {
                ZIndexUtils.set('overlay', el, this.baseZIndex + this.$primevue.config.zIndex.overlay);
            }

            this.overlayEventListener = (e) => {
                if (this.container.contains(e.target)) {
                    this.selfClick = true;
                }
            };

            OverlayEventBus.on('overlay-click', this.overlayEventListener);
            this.$emit('show');
        },
        onLeave() {
            this.unbindOutsideClickListener();
            this.unbindScrollListener();
            this.unbindResizeListener();
            OverlayEventBus.off('overlay-click', this.overlayEventListener);
            this.overlayEventListener = null;
            this.$emit('hide');
        },
        onAfterLeave(el) {
            if (this.autoZIndex) {
                ZIndexUtils.clear(el);
            }
        },
        alignOverlay() {
            DomHandler.absolutePosition(this.container, this.target);

            const containerOffset = DomHandler.getOffset(this.container);
            const targetOffset = DomHandler.getOffset(this.target);
            let arrowLeft = 0;

            if (containerOffset.left < targetOffset.left) {
                arrowLeft = targetOffset.left - containerOffset.left;
            }
            this.container.style.setProperty('--overlayArrowLeft', `${arrowLeft}px`);

            if (containerOffset.top < targetOffset.top) {
                DomHandler.addClass(this.container, 'p-overlaypanel-flipped');
            }
        },
        bindOutsideClickListener() {
            if (!this.outsideClickListener) {
                this.outsideClickListener = (event) => {
                    if (this.visible && !this.selfClick && !this.isTargetClicked(event)) {
                        this.visible = false;
                    }
                    this.selfClick = false;
                };
                document.addEventListener('click', this.outsideClickListener);
            }
        },
        unbindOutsideClickListener() {
            if (this.outsideClickListener) {
                document.removeEventListener('click', this.outsideClickListener);
                this.outsideClickListener = null;
                this.selfClick = false;
            }
        },
        bindScrollListener() {
            if (!this.scrollHandler) {
                this.scrollHandler = new ConnectedOverlayScrollHandler(this.target, () => {
                    if (this.visible) {
                        this.visible = false;
                    }
                });
            }

            this.scrollHandler.bindScrollListener();
        },
        unbindScrollListener() {
            if (this.scrollHandler) {
                this.scrollHandler.unbindScrollListener();
            }
        },
        bindResizeListener() {
            if (!this.resizeListener) {
                this.resizeListener = () => {
                    if (this.visible && !DomHandler.isAndroid()) {
                        this.visible = false;
                    }
                };
                window.addEventListener('resize', this.resizeListener);
            }
        },
        unbindResizeListener() {
            if (this.resizeListener) {
                window.removeEventListener('resize', this.resizeListener);
                this.resizeListener = null;
            }
        },
        isTargetClicked(event) {
            return (this.eventTarget && (this.eventTarget === event.target || this.eventTarget.contains(event.target)));
        },
        containerRef(el) {
            this.container = el;
        },
        createStyle() {
			if (!this.styleElement) {
				this.styleElement = document.createElement('style');
				this.styleElement.type = 'text/css';
				document.head.appendChild(this.styleElement);

                let innerHTML = '';
                for (let breakpoint in this.breakpoints) {
                    innerHTML += `
                        @media screen and (max-width: ${breakpoint}) {
                            .p-overlaypanel[${this.attributeSelector}] {
                                width: ${this.breakpoints[breakpoint]} !important;
                            }
                        }
                    `
                }

                this.styleElement.innerHTML = innerHTML;
			}
		},
        destroyStyle() {
            if (this.styleElement) {
                document.head.removeChild(this.styleElement);
                this.styleElement = null;
            }
        },
        onOverlayClick(event) {
            OverlayEventBus.emit('overlay-click', {
                originalEvent: event,
                target: this.target
            });
        }
    },
    computed: {
        containerClass() {
            return ['p-overlaypanel p-component', {
                'p-input-filled': this.$primevue.config.inputStyle === 'filled',
                'p-ripple-disabled': this.$primevue.config.ripple === false
            }];
        },
        attributeSelector() {
            return UniqueComponentId();
        }
    },
    directives: {
        'ripple': Ripple
    }
}
</script>

<style>
.p-overlaypanel {
    position: absolute;
    margin-top: 10px;
    top: 0;
    left: 0;
}

.p-overlaypanel-flipped {
    margin-top: 0;
    margin-bottom: 10px;
}

.p-overlaypanel-close {
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    position: relative;
}

/* Animation */
.p-overlaypanel-enter-from {
    opacity: 0;
    transform: scaleY(0.8);
}

.p-overlaypanel-leave-to {
    opacity: 0;
}

.p-overlaypanel-enter-active {
    transition: transform .12s cubic-bezier(0, 0, 0.2, 1), opacity .12s cubic-bezier(0, 0, 0.2, 1);
}

.p-overlaypanel-leave-active {
    transition: opacity .1s linear;
}

.p-overlaypanel:after, .p-overlaypanel:before {
	bottom: 100%;
	left: calc(var(--overlayArrowLeft, 0) + 1.25rem);
	content: " ";
	height: 0;
	width: 0;
	position: absolute;
	pointer-events: none;
}

.p-overlaypanel:after {
	border-width: 8px;
	margin-left: -8px;
}

.p-overlaypanel:before {
	border-width: 10px;
	margin-left: -10px;
}

.p-overlaypanel-flipped:after, .p-overlaypanel-flipped:before {
    bottom: auto;
    top: 100%;
}

.p-overlaypanel.p-overlaypanel-flipped:after {
    border-bottom-color: transparent;
}

.p-overlaypanel.p-overlaypanel-flipped:before {
    border-bottom-color: transparent
}
</style>
